Southern California's chances of playing in the national championship game for the third time in five years are fading. The Trojans' chances of winning at least a share of their seventh straight Pac-10 title, however, haven't looked better in months.

After winning their eighth straight game and seeing their top challenger for the conference crown fall last week, the fifth-ranked Trojans look to clinch the Pac-10 championship and a trip to the Rose Bowl when they visit crosstown rival UCLA on Saturday.

USC (10-1, 7-1) lost its conference opener to Oregon State on Sept. 25, an inauspicious start to the Trojans' defense of their six-year conference title run.

Since then, however, the Trojans have won eight straight games - including seven in conference - by an average of 33.1 points. Last Saturday, Mark Sanchez passed for 267 yards and two touchdowns, USC 's hard-hitting defense thoroughly dominated Notre Dame, and the Trojans rolled to a 38-3 victory over the Irish.

"This was a terrific way to send the seniors out," coach Pete Carroll said following his team's final home game. "We're not done yet. We just keep playing."

That win technically kept USC's national championship hopes alive, but it's unlikely they'll be able to pass three teams in the BCS standings in the final week of the regular season.

However, with Oregon State's 65-38 loss to Oregon last Saturday, USC needs only to beat UCLA (4-7, 3-5) at the Rose Bowl to win its seventh straight conference title and set up a New Year's date in Pasadena with No. 6 Penn State, the Big Ten champion.

Though the Trojans had hoped to make it back to the title game for the first time since back-to-back trips in 2004 and 2005, they are now focused on their fourth straight Rose Bowl appearance and what they hope will be their third straight win.

"Our only concern is going up to Pasadena next week and taking care of the Pac-10," linebacker Brian Cushing said after last week's game.

Cushing has been one of the many standouts on a USC defense that has put up historic numbers this season. The Trojans have allowed only 10 touchdowns in 11 games and an NCAA-low 7.8 points per game this season. No team in the country has given up fewer points per game in any of the last 13 seasons.

"Is this the best group we have had? Well, it's the best we've ever played on defense," said Carroll, whose team has ranked in the top 11 in scoring defense in four of his previous seven years with USC.

In another dominant effort last week, the Trojans didn't give up a first down until the final play of the third quarter and the Irish finished with only four first downs and 91 yards of total offense. The success of the defense has made Sanchez's job that much easier.

"They're nasty, they fight hard, they don't want to give up an inch," the junior quarterback said last Saturday.

Thanks in part to their strong defenses over the years, the Trojans have dominated their rivalry with the Bruins during Carroll's tenure. UCLA, though, has also played the role of spoiler in the crosstown series.

When these teams last met in Pasadena on Dec. 2, 2006, unranked UCLA beat then-No. 2 USC 13-9, knocking the Trojans out of the national title game.

"I know a lot of guys on the team remember that game and still have a bad taste in their mouths," USC guard Jeff Byers said Tuesday.

That defeat, which snapped USC's seven-game win streak in the series, is Carroll's only loss against UCLA. He hopes that remains the case Saturday.

"Our team gets kind of lax at times," Trojans defensive tackle Fili Moala said. "Coach does a very good job of expressing to us that this team could be a snake in the grass. We can't let that happen again."

Carroll is particularly worried about the Bruins' defense. UCLA lost 34-9 at Arizona State last Saturday, but the Arizona State defense scored all four of the team's touchdowns. The Bruins defense held the Sun Devils' offense to two field goals and 122 total yards.

"DeWayne Walker is a really good football coach," Carroll said of UCLA's defensive coordinator. "He has had tremendous success. You can't tell by the score, but the defense played like crazy (at ASU). They looked loaded up, fired-up, well-schooled, great intensity and all that. That's what gives any team a chance to beat somebody."